Nonprofits and the philanthropists behind them do an enormous amount of important work in Boston. They feed the hungry, educate children, take care of the sick, and sponsor a thriving arts and culture community. But at the upper echelons of the city, philanthropy is about something else, too. It’s about writing $10 million checks, leading $1 billion capital campaigns, getting your name stamped on college buildings, and fighting for coveted seats on prestigious boards. In other words, it’s about power—the money, influence, and ideas that make things happen. And no one in town has more of it than the leaders listed here, the 25 most powerful people in Boston philanthropy.

After talking to scores of insiders across the area, we ranked the city’s heavy hitters and examine power in all its forms—from political muscle and business influence to cultural capital and social networking.